What it does
IH DS 77 is the declarations page that accompanies ISO's Radio And Television Towers And Equipment Coverage Form (IH 00 77). The coverage form repeatedly refers to amounts "shown in the Declarations", so this page is where the scheduled property, limits of insurance, deductibles, coinsurance percentage and any changed sublimits for additional coverages are recorded.
Who needs it
Every policy that uses IH 00 77. Carriers may use their own declarations layout, but the entries the form depends on must appear somewhere in the policy.
Quoting and selling notes
Check that every scheduled item, limit and deductible matches the quote, that any changed additional coverage limits are entered (many IH form sublimits apply "unless a different Limit Of Insurance is shown in the Declarations"), and that loss payees and additional interests are listed. Review it at every renewal and when property is bought or sold.